Dish washing machines that have commercial and institutional applications are typically either high temperature machines or low temperature machines which are also known as batch machines or dump and fill machines. High temperature machines rely largely on high water temperature for sanitizing the dishware. In comparison, batch machines operate at lower water temperatures and must use chemicals for sanitization.
In both types of machines, food remnants and other debris are inevitably introduced into the wash compartment and can create a variety of problems, including clogging of the spray system and impairment of the bearings which provide rotative support for the spray arms. In order to keep the spray arm assemblies in effective operating condition, the spray arms must be disassembled, cleaned and reassembled during routine maintenance procedures that are carried out periodically. Because the operators of the machines often have somewhat low skill levels, these maintenance operations must be simple. The upper and lower spray units should be interchangeable so that they can be reversed without causing operating problems.
Regardless of how often or how thoroughly the maintenance operations are carried out, it is important to maintain the spray arm bearings free from contamination. Contamination of the bearings with various types of materials can cause them to fail prematurely and can add to the down time of the machine and the overall cost of the equipment.